java

接口的实现、继承等

 1 package test.interfacedemo; 2 import test.interfacedemo.Inter; 3  4 public class InterfaceDemo { 5     public static void main(String[] args){ 6         Inter o1 = new Foo();  //Foo实现接口Inter,类同于 向上造型 7                                //通过变量o1可以调用接口Inter中定义的方法和常量 8         System.out.println(Inter.PI); 9         10         Inter3 t = new Boo();  //Boo实现接口Inter311         t.a();12         t.c();13     }14 }

 1 package test.interfacedemo; 2  3 public interface Inter{  //接口定义 4     public static final double PI = 3.14; 5     int NUM = 5; 6     public abstract void show(); 7     void say(); //省略public abstract 8 } 9 10 class  Foo implements Inter{11     public void show(){}12     public void say(){}13 }14 15 interface Inter1{16     public abstract void a();17 }18 interface Inter2{19     public abstract void b();20 }21 interface Inter3 extends Inter1{22     public abstract void c();23 }24 25 abstract class Aoo{26     void d(){}27     abstract void e();28 }29 class Boo implements Inter3{30     void m(){}31     public void a(){32         System.out.println("a");33     }34     public void c(){35         System.out.println("c");36     }37 }38 class Coo implements Inter1,Inter2{39     public void a(){}40     public void b(){}    41 }42 class Doo extends Aoo implements Inter1,Inter2{43     void e(){}44     public void a(){}45     public void b(){}46 }